The use of radioimmunoassay for the detection of catecholamines has been described in U.S. Pat. No. 3,704,282 issued Nov. 28, 1972. While this is an extremely sensitive assay procedure, the antibody utilized therein cannot readily distinguish between closely related catecholamines and thus one obtains only an indication of total catecholamine content in the sample. Thus it would not be possible using such procedure to determine the specific presence of the individual concentrations of epinephrine type catecholamines such as epinephrine, metanephrine, synephrine or phenylephrine or norepinephrine type catecholamines such as norepinephrine, normetanephrine, octopamine or norphenephrine in a sample.
The preparation of antigens useful for eliciting antibodies selective to amphetamine analogs is disclosed in U.S. Pat. No. 3,878,187 issued Apr. 15, 1975. The antigen comprises an amphetamine hapten linked to an immunogenic protein through an alkylene oxycarbonyl linking group.
An improved fluorometric assay of catecholamines has been described by Laverty and Taylor, Analytical Biochemistry 22, 269 (1968). In such technique the catecholamines in a sample are oxidized with iodine to produce a fluorescent indole derivative which is then detected in a fluorometer. To a limited extent it is possible to measure an individual catecholamine in the presence of other related compounds. This requires the use of different oxidation pH's, different treatments of the final solution and different wavelength maxima. However, cross-interference can still arise even with the use of such conditions and thus only a very few catecholamines can actually be detected in admixture without the use of chemical separation prior to detection.